HTTPS with HAProxy and Marathon-LB for Flask docker on DCOS

I have a docker in DCOS that runs a Flask instance. I also have a marathon-lb docker with HAProxy that routes incoming traffic to that Flask docker, so I access the Flask routes in the docker like so http://{marathon-lb-docker-IP}:{service-port-of-flask-docker}/{flask-route-x}.

I would like to enable SSL for my load-balancer so that I can access my Flask docker using https instead of http, so https://{marathon-lb-docker-IP}:{service-port-of-flask-docker}/{flask-route-x}

Going through the documentation of HAProxy and marathon-lb, it’s very unclear to me how I can achieve this. Are there any guidelines/tips/suggestions on how to achieve this?